function new_pop=cross_over(pop,popsize,stringlength,dimension) 
match=round(rand(1,popsize)*(popsize-1))+1; 
  for i=1:popsize 
    %fprintf('crossover_iteacion')
    [child1,child2]=cross_running(pop(i,:),pop(match(i),:),stringlength,dimension); % match = emparejamiento cross_running 
    new_pop(2*i-1:2*i,:)=[child1;child2] 
  end 
end